18121806 has 20 divisors (see below), whose sum is σ = 40606632. Its totient is φ = 6040548.

The previous prime is 18121799. The next prime is 18121811. The reversal of 18121806 is 60812181.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 18121806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 55770 + ... + 56093.

Almost surely, 2^18121806 is an apocalyptic number.

18121806 is an abundant number, since it is smaller than the sum of its proper divisors (22484826).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18121806 is a wasteful number, since it uses less digits than its factorization.

18121806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111877 (or 111868 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 18121806 is about 4256.9714586781. The cubic root of 18121806 is about 262.6639628702.

Adding to 18121806 its reverse (60812181), we get a palindrome (78933987).

The spelling of 18121806 in words is "eighteen million, one hundred twenty-one thousand, eight hundred six".